From: Martin Lau <kafai@fb•com>
To: Steffen Klassert <steffen.klassert@secunet•com>
Cc: shengyong <shengyong1@huawei•com>, <davem@davemloft•net>,
<netdev@vger•kernel.org>, <yangyingliang@huawei•com>,
<hannes@redhat•com>, Kernel Team <Kernel-team@fb•com>
Subject: Re: [PATCH RFC 1/3] ipv6: Fix after pmtu events dissapearing host routes
Date: Mon, 30 Mar 2015 11:24:33 -0700 [thread overview]
Message-ID: <20150330182433.GC2303816@devbig242.prn2.facebook.com> (raw)
In-Reply-To: <20150330103313.GJ3311@secunet.com>
On Mon, Mar 30, 2015 at 12:33:13PM +0200, Steffen Klassert wrote:
> We currently don't clone host routes before we use them.
> If a pmtu event is received on such a route, it gets
> an expires value. As soon as the expiration time is
> elapsed, the route is deleted. As a result, the host
> es not reachable any more.
s/es/is
> We fix this by cloning host routes if they are not local,
> i.e. if pmtu events can happen. Also adjust the route
> deletion because the cached and the original host route
> are on the same fib node.
>
> Signed-off-by: Steffen Klassert <steffen.klassert@secunet•com>
> ---
> net/ipv6/route.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
> index 4688bd4..4318626 100644
> --- a/net/ipv6/route.c
> +++ b/net/ipv6/route.c
> @@ -961,7 +961,7 @@ redo_rt6_select:
>
> if (!(rt->rt6i_flags & (RTF_NONEXTHOP | RTF_GATEWAY)))
> nrt = rt6_alloc_cow(rt, &fl6->daddr, &fl6->saddr);
> - else if (!(rt->dst.flags & DST_HOST))
> + else if (!(rt->dst.flags & DST_HOST) || !(rt->rt6i_flags & RTF_LOCAL))
> nrt = rt6_alloc_clone(rt, &fl6->daddr);
I suspect the nrt and rt will share the same inetpeer. Hence, after the nrt is
removed, the MTU (obtained from PMTU update) will stay.
> @@ -1796,6 +1796,8 @@ static int ip6_route_del(struct fib6_config *cfg)
> continue;
> if (cfg->fc_metric && cfg->fc_metric != rt->rt6i_metric)
> continue;
> + if (!(cfg->fc_flags & RTF_CACHE) && (rt->rt6i_flags & RTF_CACHE))
> + continue;
> dst_hold(&rt->dst);
> read_unlock_bh(&table->tb6_lock);
>
> @@ -2433,6 +2435,9 @@ static int rtm_to_fib6_config(struct sk_buff *skb, struct nlmsghdr *nlh,
> if (rtm->rtm_type == RTN_LOCAL)
> cfg->fc_flags |= RTF_LOCAL;
>
> + if (rtm->rtm_flags & RTM_F_CLONED)
> + cfg->fc_flags |= RTF_CACHE;
> +
> cfg->fc_nlinfo.portid = NETLINK_CB(skb).portid;
> cfg->fc_nlinfo.nlh = nlh;
> cfg->fc_nlinfo.nl_net = sock_net(skb->sk);
I had pulled your last patch to my local branch that I am cooking. I also
added similar changes to ip6_route_del() and rtm_to_fib_config(), and confirmed
it can keep 'ip -6 r del' and 'ip -6 r flush table cache' to keep working
properly.
Thanks,
--Martin
next prev parent reply other threads:[~2015-03-30 18:24 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-02 8:20 Question: should local address be expired when updating PMTU? shengyong
2015-02-02 21:31 ` David Miller
2015-02-03 0:52 ` Alex Gartrell
2015-02-03 1:28 ` shengyong
2015-02-03 2:10 ` Calvin Owens
2015-02-03 3:21 ` shengyong
2015-02-03 9:28 ` Steffen Klassert
2015-02-03 10:54 ` shengyong
2015-02-03 12:01 ` Steffen Klassert
2015-02-04 1:59 ` shengyong
2015-02-05 7:21 ` Steffen Klassert
2015-02-27 2:37 ` shengyong
2015-02-27 10:32 ` Steffen Klassert
2015-03-30 10:32 ` Steffen Klassert
2015-03-30 10:33 ` [PATCH RFC 1/3] ipv6: Fix after pmtu events dissapearing host routes Steffen Klassert
2015-03-30 11:15 ` Sheng Yong
2015-03-30 18:24 ` Martin Lau [this message]
2015-04-01 8:09 ` Steffen Klassert
2015-03-30 10:33 ` [PATCH RFC 2/3] ipv6: Extend the route lookups to low priority metrics Steffen Klassert
2015-03-30 10:34 ` [PATCH RFC 3/3] ipv6: Don't update pmtu on uncached routes Steffen Klassert
2015-03-30 11:13 ` Question: should local address be expired when updating PMTU? Sheng Yong
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